This invention relates to abrasive article having universal hole patterns for use on sanding machines having differing extraction hole patterns.
Today, many different manufacturers sell orbital or random orbit sanding machines or sanders usable with removable and replaceable abrasive discs that are typically mounted to a back-up pad. Many of these sanding machines include integral or attachable vacuum extraction systems. However, these sanding machines are currently available with many different extraction hole patterns formed within the backup pad for use with the extraction systems. The extraction systems help to remove the large amount of dust and particles generated by the sanding process. This dust is not only a nuisance and a cleanliness issue, but can also cause health concerns and limit the useful life of the abrasive disc. Abrasive discs for use with these different sanders are available with the discs adapted to the different dust extraction hole patterns and numbers of holes in each pattern. This allows the sanding dust to be effectively removed from the work piece while the sanding operation is being performed, which helps maintain a cleaner work environment and prolong the life of the abrasive disc.
In the U.S. retail market, there are two predominate extraction hole patterns for sanding machines using five inch diameter sanding or abrasive discs. FIG. 1 illustrates a mounting surface 20 for a dust extraction system having five dust extraction holes 22 each with diameters of about xe2x85x9c inch (9.53 millimeters) that are located on about a 2.766 inch (70.26 millimeter) diameter circle. FIG. 2 illustrates a mounting surface 24 for a dust extraction system having eight dust extraction holes 26 each with diameters of about xe2x85x9c inch (9.53 millimeters) that are located on about a 2.626 inch (66.70 millimeter) diameter circle. The holes 22, 26 are fluidly coupled to an extraction manifold. The mounting surfaces 20, 24 can be located directly on the sanding machine or can be an intermediate back-up pad, such as a foam or non-woven material, attached to the sanding machine.
Prior art abrasive discs typically include a pattern of holes that substantially correspond to the pattern of holes 22, 26 illustrated in FIGS. 1 and 2. The prior art abrasive discs must be oriented so that their holes are substantially aligned with the holes 22, 26 on the mounting surfaces 20, 24, respectively.
Use of these discs includes attachment of the discs, usually by adhesive, hook and loop fasteners or other conventional means, onto the back-up pad of the sander being used while aligning the hole pattern in the abrasive disc with the extraction hole pattern in the back-up pad. Effective functioning of the dust extraction system does not require a 100 percent alignment between the holes in the disc and the extraction holes resulting in 100 percent exposure of the extraction holes. Rather, it has been found that an alignment or exposure of 75 percent or greater is generally preferred for efficient operation of the extraction system.
Due to the lack of hole pattern standardization, numerous dust extraction hole patterns are currently available on sanding machines. Therefore, abrasive disc manufacturers, wholesale sellers and retailers must make and/or stock discs with each pattern in all ranges of abrasive grit for use with these sanding machines. This increases the cost, inconvenience and stocking difficulty in trying to meet the customer""s needs. In order to reduce these problems, attempts have been made to provide a solution to the multiple pattern situation. U.S. Pat. No. 5,989,112 (Long et al.) discloses an abrasive disc having an eight hole pattern in which some of the holes are enlarged to encompass some of the holes of the five hole pattern. U.S. Pat. No. 5,810,650 (Jxc3x6st) discloses the provision of a multitude of smaller holes or perforations distributed evenly over the surface of the abrasive disc, which don""t necessarily align directly with the smaller number of larger dust extraction holes in the sanding machine.
The present invention is directed to an abrasive article with a plurality of apertures that can be used with at least two different dust extraction systems each having a different number or configuration of dust extraction holes. The number of apertures in the abrasive article corresponds generally to the number of dust extraction holes. The apertures are typically concentrated in a region corresponding to the location of the dust extraction holes. The arrangement of the apertures permits the abrasive article to be mounted to the dust extraction system in any angular orientation when the abrasive article is in registration with the mounting surface. That is, the present abrasive article is orientation independent relative to the dust extraction holes, while still providing adequate exposure of the dust extraction holes by the discrete apertures.
One embodiment of the present abrasive article comprises a disc capable of being used with both the five-hole and eight-hole dust extraction patterns currently available commercially for sanding machines. The various embodiments illustrate apertures that may be readily aligned by the user with the dust extraction holes on the sander mounting surface without regard to angular orientation, while providing suitable extraction efficiency. These embodiments also include sufficient abrasive material to provide adequate sanding cut rate and structural integrity during use and removal.
The abrasive article of the present invention is adapted to mount on a mounting surface of a sanding machine having a plurality of dust extraction holes defining an open area. The abrasive article includes a plurality of discrete apertures sized and positioned so as to expose a majority of the open area of the dust extraction holes independent of the angular orientation of the abrasive article when the abrasive article is in registration with the mounting surface. For use with the abrasive article of the present invention, the plurality of dust extraction openings may include five or eight openings.
The abrasive article may be formed as elongated slots, and in particular, elongated, arcuate slots. The slots may have radiused ends. The discrete apertures may include elongated, arcuate slots each having an inner radius of about 1.13 inches (28.70 millimeters) from a center point of the abrasive article and a width of about 0.44 inches (11.18 millimeters). In one embodiment, the discrete apertures may include seven elongated, arcuate slots each having an arc length that ranges from about 0.87 inches (22.10 millimeters) to about 1.06 inches (26.92 millimeters). Alternatively, the discrete apertures may include three elongated, arcuate slots each having an arc length that ranges from about 2.21 inches (56.13 millimeters) to about 2.57 inches (65.27 millimeters).
The discrete apertures may be symmetrically arranged around a center point of the abrasive article, and may be generally of the same size or of different sizes. The discrete apertures may be arcuate slots of differing lengths. In addition, the discrete apertures of the abrasive article may expose at least about 75% of the open area. They may also encompass an area less than about 30 percent of an area of the abrasive article. In one embodiment, the discrete apertures include seven discrete apertures and in another embodiment, the discrete apertures may include less than ten discrete apertures.
The present invention is also directed to a method of manufacturing a universal abrasive article adapted to mount on a mounting surface of a sanding machine having a plurality of dust extraction holes defining an open area. The method includes the steps of providing an abrasive article suitable for mounting to the mounting surface, and forming a plurality of discrete apertures that are sized and positioned so as to expose a majority of the open area of the dust extraction holes independent of the angular orientation of the abrasive article when the abrasive article is in registration with the mounting surface.